强调句型三种结构是什么？
强调句型三种结构：
(1)强调句型的一般结构是“It is/was+被强调部分+that/who+其他成分”，it在句中无意义，只起引出被强调部分的作用。强调人时可用that/who来连接，其他情况一律用that。
It was I that/ who didn’t realize all my mistakes until you told me yesterday. (强调主语)
It was all my mistakes that I didn’t realize until you told me yesterday. (强调宾语)
It was not until you told me yesterday that I realized all my mistake. (强调状语)
(2)强调句型一般疑问句形式：Is/ Was it+被强调部分+that/ who+其他部分。
(3)强调句型的特殊疑问句形式：特殊疑问词+is/was+it+that+该句的其余部分，that后只能使用陈述语序。
When was it that you met the pop star? 你是什么时候见到的超级明星?
(4)在“not...until”强调结构中，由until所引导的短语或从句作时间状语时，要用固定的强调句型：It+is/was+not until...+that+该句的其余部分，that所引导的从句中的谓语动词用肯定式。例如It was not until you came back that I finished the work. 直到你回来我才完成工作。
强调句型举例
原句： My father did the experiment in the lab yesterdayevening.
强调主语： Itwas my father who did the experiment in the lab yesterday evening.
强调宾语权： Itwas the experiment that my father did in the lab yesterday evening.
强调时间： Itwas yesterday evening that my father did the experiment in the lab.
强调地点： Itwas in the lab that my father did the experiment yesterday evening.
